JP2018137329A - Electronic control unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic control device suitable for miniaturization capable of securing resistance to exposure to electromagnetic waves by having high suppression efficiency of the electromagnetic radiation amount to the outside without inhibiting heat dissipation efficiency of heat generated by an electronic element in a casing.SOLUTION: A structure containing a periodic structure is periodically installed between an electronic element or a substrate on which an electronic element is mounted and a casing including an electronic element or a substrate on which an electronic element is mounted.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electronic control device.

  As a background art in this technical field, there is JP-A-2009-212198 (Patent Document 2). In this publication, “the opening size of the metal housing and the arrangement of the circuit board as the electronic device in the housing are optimized to reduce the intrusion of electromagnetic waves from the outside of the metal housing, thereby "Provides a reduced electronic equipment housing".

  Moreover, there exists Unexamined-Japanese-Patent No. 2011-18776 (patent document 3). In this publication, “a conductive material accommodating portion that accommodates an electronic circuit in an internal space, and a current having a resonance frequency of the accommodating portion that is provided in a current path of a current that flows through the accommodating portion by the operation of the electronic circuit. It is described as “a container for accommodating an electronic circuit provided with a suppressing member that suppresses the above”.

  Moreover, there exists Unexamined-Japanese-Patent No. 2002-217343 (patent document 1). An elastic heat dissipating sheet is interposed between the heat generating component mounted on the board and the heat dissipating plate, and heat generated from the heat generating component is transmitted to the heat dissipating plate via the heat dissipating sheet and released to the outside. As a result, it is described as “to achieve a high heat dissipation effect for the heat-generating component with a simple configuration”.

  Moreover, there exists Unexamined-Japanese-Patent No. 2015-135979 (patent document 4). This publication states that “provides a heat sink including an electromagnetic bandgap structure that reduces electromagnetic interference caused by integrated circuits in electronic devices”.

JP 2002-217343 A JP 2009-212198 A JP 2011-18776 A Japanese Unexamined Patent Publication No. 2015-135579

  Electronic control devices, particularly automobiles, are equipped with electronic control devices such as an engine control unit and an automatic transmission control unit, and the electronic control device performs electronic control of the vehicle. In automobiles, the weight reduction of the vehicle itself is progressing, and the object of weight reduction extends not only to the vehicle body but also to the electronic control device, and most of the electronic control device cases conventionally formed of metal or conductive material. Is made of non-conductive resin.

  In addition, the electronic control device is required to operate stably due to electromagnetic interference caused by close proximity to each other or electromagnetic interference from the external environment. Regulations regarding EMC (Electromagnetic Compatibility) are provided to limit the amount of electromagnetic radiation generated by an electronic control device and the like and to ensure resistance to electromagnetic wave exposure so that the electronic device operates normally. For example, in automobiles, a standard called CISPR (Commit International Specialties Radioelectrics) 25 is established internationally, and the amount of electromagnetic radiation in the electronic control device itself is below a prescribed value, and further, the electronic control device is Even when installed in a radiation field, it must be confirmed that it operates normally.

  When most electronic control unit cases are made of resin, the non-conductive resin has a high electromagnetic wave transmittance. Therefore, it is made of a metal or conductive material as described in Patent Document 1 and Patent Document 2. Compared to the formed housing, it becomes easier to enter the case together with the radiation of the electromagnetic wave to the outside of the case, and thus it becomes difficult to ensure the resistance to the electromagnetic wave exposure.

  In addition, since the electronic element mounted on the electronic control device itself generates heat and causes a malfunction of the electronic element due to a rise in temperature, heat from the electronic element must be radiated to the outside of the housing. As a technique for radiating the heat generated by the electronic element to the outside of the housing, a heat radiating member such as copper having a high thermal conductivity is attached to the electronic device or directly attached to the conductor housing. However, in the former case, since the heat radiating member is not in contact with the housing, the heat transfer from the heat radiating member to the housing must be based on natural convection heat transfer, and the amount of heat radiated from the heating element is limited. In the latter case, although the amount of heat released from the heating element can be increased, the terminals of the heating element and the substrate are electrically connected by lead wires, which increases the number of assembly steps of the electronic device and increases the cost. In addition, since the heating element is attached to the housing, there is a problem that the arrangement of other electronic components on the substrate is limited. Further, in any of the methods, the fixing of the heat generating element to the heat radiating member or the casing is performed by screwing, so that the number of assembling steps increases.

  The configuration disclosed in Patent Document 1 described above has a problem that electromagnetic radiation to the outside due to the operation of the electronic element cannot be suppressed.

  In addition, the heat sink disclosed in Patent Document 4 described above has a problem that it is difficult to apply to an electronic control device that is required to be downsized, for example, used in an automobile.

  Moreover, in the structure which the whole housing | casing disclosed by the above-mentioned patent document 2 and patent document 3 consists of metal, it is difficult to apply, for example in the electronic control apparatus by which weight reduction used for a motor vehicle is calculated | required. There was a problem.

  The present invention provides an electronic control device suitable for miniaturization, which does not impede the heat dissipation efficiency of heat generated by the electronic elements in the enclosure, has high efficiency of suppressing the amount of electromagnetic radiation to the outside, and at the same time can secure resistance to electromagnetic wave exposure. The purpose is to do.

  In order to achieve the above-mentioned object, the present invention provides an electronic control device in which a substrate on which an electronic element that radiates or is exposed to electromagnetic waves by operation is mounted is housed in a housing. A structure for attenuating the outside of the substrate is periodically provided between the electronic element and the housing.

  According to the present invention, the heat dissipation efficiency of the heat generated by the electronic elements in the housing is not hindered, the efficiency of suppressing the amount of electromagnetic radiation to the outside is high, and at the same time, resistance to electromagnetic wave exposure can be secured, which is suitable for downsizing. An electronic control device can be provided.

  Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

It is sectional drawing (A) which shows the structure of the electronic controller which concerns on Example 1 of this invention, and the top view (B) of a base board and a structure. It is a figure which shows the frequency dependence of the attenuation amount of the electromagnetic radiation which concerns on Example 1 of this invention. It is sectional drawing which shows the structure of the electronic controller which concerns on Example 2 of this invention. It is sectional drawing which shows the structure of the electronic controller which concerns on Example 3 of this invention.

Embodiments of the present invention will be described below with reference to the drawings.

[Example 1]
FIG. 1A is a cross-sectional view of an electronic control device 100 according to an embodiment of the present invention, and FIG. The top view of the composite structure 121,122,123 consisting of the conductor which has is shown. Here, it is a diagram schematically showing an essential part of the present invention, and in general, various types of electronic elements are mounted on a circuit board (hereinafter simply “substrate”) 104. Yes.

  The substrate 104 is fixed to a plurality of conductive columns 102 and 103 of a conductive base plate 101 forming a part of the case of the electronic control element by a plurality of conductive screws 105 and 106. The substrate 104 generally has a structure composed of a power supply layer, a ground layer, a signal layer and the like, vias connecting them and an insulating layer between the layers, and the ground layer is composed of pillars 102, 103 and a base by screws 105, 106. Connected with the board. Hereinafter, of the two large surfaces of the substrate 104, the surface on the conductive base plate 101 side forming a part of the case of the electronic control element is referred to as the lower surface of the substrate, and the surface opposite to the base plate 101 is referred to as the upper surface of the substrate. I will decide. The above components other than the base plate 101 are covered with a resin cover 107.

  Between the substrate 104 and the base plate 101, the structures 121, 122, and 123 are periodically arranged in the substrate plane direction (or the base plate plane direction). On the upper surface of the substrate corresponding to the lower surface portion of the substrate where the structures 121, 122, 123 and the substrate 104 are in contact, a plurality of electronic elements 108, 109, 110, 111, 112, etc. with high heat generation are arranged and mounted. .

  The structures 121, 122, and 123 are composite structures including a dielectric having high thermal conductivity and a conductor having a periodic structure. The contact surface between the substrate 104 and the base plate 101 and the structure is made up of a dielectric material.

  2 shows the attenuation of electromagnetic radiation in the case of the electronic control device in which the structures 121, 122, 123 shown in FIG. 1 are installed and in the case of the electronic control device in which the structures 121, 122, 123 are not installed. It is the graph which compared the frequency dependence of quantity. In FIG. 2, the horizontal axis represents frequency, and the vertical axis represents electromagnetic radiation attenuation. In the frequency band range of 2 GHz to 4 GHz, the electromagnetic radiation attenuation when the structures 121, 122, 123 are not installed is higher when the structures 121, 122, 123 are installed. Therefore, the amount of electromagnetic radiation leaking outside the electronic control device is low. Electronic elements that generate a large amount of heat are often elements that radiate electromagnetic waves. For this reason, the periodic structure may be set so as to attenuate the frequency of the electromagnetic wave emitted by the electronic element.

  FIG. 2 shows the results when the conductors of the structures 121, 122, and 123 are made of copper and the dielectric is made of a mixture of silicone and alumina. However, the material structure of the structure is not limited to this, A magnetic material or the like may be used.

  In addition, the result of FIG. 2 shows that the attenuation is high with a peak near the frequency of 3.1 GHz. However, the structure 121, 122, 123 is attenuated by forming the structure of a so-called EBG (Electromagnetic Band Gap) structure. It is possible to adjust the frequency so that the frequency of the peak, the width of the peak, and a plurality of frequencies can be handled. The structures 121, 122, and 123 may not all have the same frequency characteristics. For example, the peak frequency corresponding to the structure 121 and the peak frequency corresponding to the structures 121 and 123 are shifted by a factor of two. Also good. That is, the periodic structure includes a plurality of periodic patterns having different periods.

  In addition, an element with a high calorific value does not necessarily have to be mounted on the upper surface of the substrate corresponding to the lower surface of the substrate where the periodically arranged structural bodies 121, 122, 123 and the substrate 104 contact.

  Further, when exposed to electromagnetic waves, electromagnetic waves may enter the space surrounded by the substrate 104 and the plurality of conductive columns 102 and 103 of the conductive base plate 101, causing resonance at a frequency specific to the space. However, by periodically disposing the structures 121, 122, and 123, it is possible to attenuate electromagnetic waves having a resonance frequency when the structures are not installed. The arrangement method can be changed according to the corresponding frequency.

  As described above, according to the present embodiment, in the electronic control device 100, heat dissipation performance of heat generated by a plurality of electronic elements having a high calorific value can be ensured, diffusion of electromagnetic waves is suppressed, and resistance to electromagnetic wave exposure is ensured. can do.

[Example 2]
FIG. 3 shows a cross-sectional view of an electronic control device 300 according to the second embodiment. In the electronic control device of the first embodiment, a composite structure composed of a dielectric material having high thermal conductivity and a conductor having a periodic structure is formed on the conductive base plate 101 that forms part of the case of the electronic control element. Although directly arranged, for example, 301, 302, 303 are provided as convex parts integrally formed with the base plate 101 by aluminum die casting, and a dielectric material having high thermal conductivity and a conductor having a periodic structure are provided thereon. Composite structures 321, 322, and 323 are provided. As described above, for example, when using a material that is difficult to form a structure with a high aspect ratio, or when the material cost for forming the structure is expensive, an electron having the same effect as that of the first embodiment can be obtained. A control device can be provided.

[Example 3]
FIG. 4 is a cross-sectional view of an electronic control device 400 according to the third embodiment. This is a case of so-called double-sided mounting, and the electronic element 409 having a high calorific value is mounted on the back surface of the substrate. In this case, the structure body 422 is provided between the electronic element 409 having a high calorific value and the convex portion 402 of the conductive base plate.

  Also in this case, the electronic control device 400 can secure the heat dissipation performance of the heat generated by the plurality of electronic elements having a high calorific value, suppress the diffusion of the electromagnetic wave, and ensure the resistance to the electromagnetic wave exposure.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 100, 300, 400 ... Electronic control device 101 ... Base board 102, 103 ... Post 104 ... Circuit board 105, 106 ... Screw 107 ... Cover 108, 109 of case 110, 111, 112, 409 ... electronic elements 121, 122, 123, 321, 322, 323, 422 ... structural bodies 301, 302, 303, 402 ... convex portions of the base plate of the case

Claims (6)

An electronic element, a board on which the electronic element is mounted, and a housing for mounting the board inside,
An electronic control device having a periodic structure periodically arranged between the housing and the substrate in a planar direction of the substrate   2. The electron according to claim 1, wherein the periodic structure is a structure provided to have a period for attenuating an electromagnetic wave having a frequency emitted by the electronic element and a period for attenuating an electromagnetic wave having a frequency entering from the outside of the housing. Control device   The electronic control device according to claim 1, wherein the housing includes a metal base and a resin cover, and the periodic structure is disposed between the metal base and the substrate.   The electronic control device according to claim 1, wherein the periodic structure is made of a material including a dielectric or a magnetic material.   The electronic control device according to claim 3, wherein the periodic structure includes a periodic protrusion formed on the metal base and a dielectric provided on the protrusion.   The electronic control device according to claim 1, wherein the periodic structure includes a plurality of periods.

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